Blank screen on startup

As the title says I start up my computer and get blank screen. I have tested with 2 monitors so thats not the problem. I have changed the ram so that appears not to be the problem either. I have made a vid:

youtube.com/watch?v=qLoA2I_x-Rc

and heres a pic of my motherboard:

b.imagehost.org/view/0428/DSCI0521

Any suggestions would be welcome.
The computer was shipped from poland to Ireland, something must have gone wrong on the way.

that green cable with 4 connections is for a different sort of motherboard.
when you start this there is no beep from the speaker - see if you can reconnect this and then tell us how many beeps you get when you turn it on, One beep is good - many beeps is not good but should give a clue as to what is missing.

Is the voltage setting correct?
I noted from the video that the power light and the HDD lights looked as if they were already on before you started the system - is this so?

do you have a manual for the motherboard - if you can find the right pair of jumper pins you could short out the BIOS for 10 secs and reboot to see it that sorts it out. I cannot hear the single beep but believe you!
Also check the motherboard connections - I have seen this before when the wrong cable was connected across the reset button pins - this would also explain why the power light and HDD activity light are both on (on the front of the PC case) - best bet is to disconnect them all and start the PC with a screwdriver across the power button pins. If you have the manual it will help you find which pair of pins to use.

I changed the psu just in case it was that but no luck, same problem. I connected a different HDD from another computer but again same story. I don't have a manual for the motherboard. If it is the motherboard I think I will have to concede defeat on this one.

As I suggested in my last post, check the mother board connections from the front panel of the PC case. Unplug the lot and restart with a screwdriver across the pins for the pwr connection - it will be marked on the board for you.
Those lights on the front should not be illuminated unless the PC is running - they appeared to be lit before you powered it on in your video.
Let us know what happens - it would be a shame to chuck the board if it was simply down to the wrong thing being connected!